Re: [RFC PATCH] platform: Faciliatate the creation of pseduo-platformbusses

From: Patrick Pannuto
Date: Tue Aug 03 2010 - 20:18:09 EST

>>>> struct platform_device sub_bus1 = {
>>>> .name = "sub_bus1",
>>>> .id = -1,
>>>> .dev.bus = &my_bus_type,
>>>> }
>>>> EXPORT_SYMBOL_GPL(sub_bus1);
>>> You really want a bus hanging off of a bus? Normally you need a device
>>> to do that, which is what I think you have here, but the naming is a bit
>>> odd to me.
>>> What would you do with this "sub bus"? It's just a device, but you are
>>> wanting it to be around for something.
>> It's for power management stuff, basically, there are actual physical buses
>> involved that can be completely powered off IFF all of their devices are
>> not in use. Plus it actually matches bus topology this way.
> Then create a real bus hanging off of a device, not another device that
> "acts" like a bus here, right? Or am I missing the point?

The motivation for doing it this was is that one driver could drive
devices on two different subbusses. In the example, "my-driver" could
drive a device on sub_bus1 AND sub_bus2 (if there were 2+ devices, one
or more on each bus).

>From my understanding, this is not possible if they are actually
different busses.
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